1. Field of the Invention
The field of art to which this invention pertains is boomerang projectiles.
2. Description of the Prior Art
In the prior art toys that made noises did not have the capacity for returning to the thrower. Within U.S. Pat. No. 4,080,753 an alternate embodiment of a conventional boomerang shape is described, but the flight path illustrated and described is clearly non-returning. The preferred embodiment for a flying saucer uses a buzzer which only produces sound while rotating. This same lack of continuous sound production is true of several throwing balls in U.S. Pat. Nos. 1,187,838; 1,193,992; 620,084; 163,086; 2,687,302; 1,628,717; and 3,395,462 which would not continue to produce sound long enough to retrieve from under parked cars or dislodge from a tree, which would be crucial to the visually impaired individual.
In the prior art toys that performed as a true boomerang, flew largely parallel to the ground on a flight path generally describing a circle and returned to the thrower, but did not produce a continuous sound. Visually impaired individuals, therefore, could not perceive the location of such boomerangs nor reasonably partake in the sport.
In the prior art many things are considered boomerangs. Many objects referred to as boomerangs do not have the capability of returning to the starting point exhibited by true boomerangs. The flight of the boomerang requires a delicate balance of forces to fly in the circular path described by FIG. 10 where the user 50 throws the boomerang 40 at tilt that is largely vertical as opposed to the horizontal orientation for optimum performance of disks referred to as "Frisbees."
The physical principles involved include:
(1) The lift force created by an airfoil slicing through the air. As shown in FIG. 8, as the air foil 32 travels toward point W, the air is forced to pass above and below the airfoil 32. The air passing over the airfoil 32, i.e. point X, is rarified because the same quantity of air passes above and below, but travels a larger distance passing above the airfoil 32. This reduces the air pressure at point X such that the pressure at Y is greater causing a force in direction S.
(2) As the boomerang is thrown forward while spinning, the airfoil in the upper position V always passes through more air because it is both rotating and translating into oncoming air. The airfoil at position U therefore experiences less lift force.
(3) As seen in FIG. 11, a side view of the rotating boomerang, the greater force on the upper portion of the rotating boomerang causes a perpendicular twisting force about the axis that runs from top to bottom. This torque I, is often referred to as "gyroscopic precession" and is a result of the conservation of angualr momentum.